Enhanced thermoelectric and mechanical properties of p-type skutterudites with in situ formed Fe3Si nanoprecipitate

摘要

In the present work, p-type skutterudites La_(0.8)Ti_(0.1)Ga_(0.1)Fe3CoSb_(12) composite with n-type Fe3Si nano- precipitate was fabricated via an in situ method. Both thermoelectric and mechanical properties of La_(0.8)Ti_(0.1)Ga_(0.1)Fe3CoSb_(12)/ Fe3Si composites were thoroughly investigated. With the introduction of homo- geneously dispersed nanosized Fe3Si in the matrix, the power factor is almost unchanged due to the counteraction between the decreased electrical conductivity and the significantly enhanced Seebeck coefficient. Simultaneously, the total thermal conductivity was decreased for samples with Fe3Si nano- precipitate because of the reduced electronic thermal conductivity. As a result, a ZT value of about 1.2 at 700 K has been achieved for La_(0.8)Ti_(0.1)Ga_(0.1)Fe3CoSb_(12)/0.1Fe3Si sample, whose ZT value was slightly enhanced in comparison with the Fe3Si-freeLa_(0.8)Ti_(0.1)Ga_(0.1)Fe3CoSb_(12) sample. Furthermore, the indenta- tion fracture toughness of La_(0.8)Ti_(0.1)Ga_(0.1)Fe3CoSb_(12)/0.1Fe3Si was improved by nearly 30% compared to the Fe3Si-free skutterudites.